Suction box top for papermaking machines



J. PROULX SUCTION BOX TOP FOR PAPER MAKING MACHINES April 18, 1944.

Fiied Oct. 15. 1942 Inventor JEAN mom 7 I by Attorney.

ranged with the grain of the Patented Apr. 18 1944 SUCTION BOX TOP FOR PAPERMAKIN G MACHINE Jean Proulx, Hull, Quebec, Canada Application October 15, 1942, Serial N05 462,449

3 Claims.

This invention relates to new and useful improvements in a suction box top for paper making machines and in particular to such a. top composed of a row of short-length wood blocks, placed one against the other across the width of the. suction box, wherein the blocks are arwood runlning vertically.

An object of the invention is to provide a suction box top of end-of-grain wood blocks that will last longer than ordinary suction box covers now in use and reduce the friction and wear on and materially increase the useful life of the expensive Fourdrinier wire screen passing over it, is much easier and cheaper to resurface, taking only a small fraction of the time to plane that is now required and, having suction bores flaring toward the bottom, cannot clog.

A furtherobject of the invention is to provide a suction box top of a row of end-of-graln wood blocks wherein the short-length wood blocks will not check, warp, shrink or swell when in use, the individual short-length blocks being thoroughly impregnated with a waxy composition that controls the soaking and evaporation.

A further object of the invention is the provision of a short-length, end-of-grain wood block for a suction box top of the nature and for the purposes described that is characterized by structural simplicity, efilciency and economy in use and being capable of production easily and cheaply, is thereby rendered commercially desirable.

To the accomplishment of the above and related objects, the invention resides in the construction, combinatien and arrangement of parts as shall be hereinafter more fully described, illustrated in the accompanying drawing, and pointed out in the claims hereunto appended.

The invention will be best understood and can be more clearly de cribed when reference is had to the drawing forming a part of this disclosure wherein like characters throughout the several views.

In the drawing:

Figure 1 is a plan view of a part of a suction box cover composed of my improved end-ofgrain wood blocks; and

Figure 2 is a vertical section thereof taken on line 2-2.

For .this suction box top, hard maple blocks, approximately 2 inches in thickness are preferred. Dry wood, not kiln dried, with a moisture content of approximately 6% should be used.

indicate like parts These blocks are thoroughly impregnated with a waxy composition, so that the fibres are saturated and the pores and cells loaded completely, and then shaped and bored to specification to lit the particular suction box for which they are intended. As the suction box is constantly wet in operation, the blocks until wanted are best stored in a cool damp place.

In use, the end-of-grain blocks have been found to wear .threetimes as long as the old long-plank type of suction box cover. Further, the expensive Fourdrinier wire screens used with them last much longer and the consequent saving of time in the greatly reduced servicing of both suction box tops and wires has resulted in substantial economics in the paper mills. Added to these improvements, now, are the advantages of the suction box top made of end-of-grain wood blocks when thoroughly impregnated with a waxy solution.

Because the blocks are short, only 2 inches or so in thickness, a type of complete impregnation is obtainable that under other conditions would be extremely difilcult and expensive, if indeed possible. A suitable waxy solution is composed primarily of a very hard paraflln wax and withthis quantity of lanolin varying from to 10%. This solution has certain very desirable features; the lanolin is slightlymiscible and increases the plasticity of the very hard paraflin,

.it is absorbed by and saturates the wood fibres whose ends are at least partially sealed with the wax that serves to further retard any washing away, while the lanolin-saturated fibres will not be alternately soaking up water and drying out to squeeze and enlarge and squeeze and enlarge the wax filled cells and pores; in this way the lanolin and wax co-operate in protecting each other. That the cells and pores, all the way through the blocks, should be loaded with a very hard wax is important. If they be not so, the initial finishingof the block, which would expose the deficiency, would be rendered the more difficult. Of greater importance, however, is the fact that insufi'icient or incomplete impregnation will cause the blocks to check, warp or shrink and swell and in the course of time the blocks would pick up a lot of grit that would lodge in the pores adding greatly to the wear on the Fourdrinier wire screen and when the replaning of the suction box top was necessary, a. days time would be taken whereas an hour or so would suflice with properly waxed blocks.

An additional economy and greater efficiency results from these thoroughly waxed blocks in that the "tapered" bores or suction holes that flare to the bottom, which is the outlet. are positively non-clogging. This saves frequent stoppages and time-out periods for washings. If the waxirig'be not complete and some pores or cells be not fully loaded the grit and pulp will tend to cling and gradually accumulate, slowly closing the passages until eventually they are blocked. This tendency to block the bores or suction holes was largely overcome by the thorough waxing; combined, however, with the "tapered or downwardly flaring openings it has been completely eliminated.

In the attached drawing, the paper mill suction box I, shown in Figure 2 in section, is provided with a cover composed of a plurality of diagonally disposed wood blocks 2 in which the grain runs vertically, or substantially so. These short length, end-of-grain blocks are carefully prepared to fit the instant suction box I and to engage tightly against each other after a wax impregnating treatment of which a description follows. v

Following the waxing and shaping of the blocks 2 they are bored to provide suction holes 3 that are reamed out from the bottom to give' a taper that opens out or flares to the bottom. The holes 3 shown are circular bores but the terms suction holes and bores are'used generally to denote the passages through the suction box cover without regard to their particular crosssectional shape, as various designs and shapes of such holes or slots are commonly used in the making of various kinds of paper. In this particular kind of suction box cover, made from end-of-grain wood blocks, an improved result has been observed in the use of the tapered hole in a wax filled block.

The block is necessarily fully loaded or wax impregnated to obtain the maximum in increased eflicient and economic operations, as referred to hereinbefore. This waxing, or more particularly impregnating with a waxy composition, may be accomplished in several ways, as follows:

1. The short-longth end-of-grain blocks are stacked in a tank, immersed in a mixture of a very hard paraffin wax and lanolin, and subjected to heat and pressure.

- 2. Alternately, the blocks may be first treated, under heat and pressure to just the lanolin and subsequently to the wax, likewise under both heat and pressure.

In these cases, the blocks are best heated for an hour or so to obtain an even heat throughout, immersed in the molten wax and/or lanolin for a period of 3 to 6 hours and heated to a temperature of approximately 212 under 50 pounds pressure, then allowed to cool gradually. absorbing the wax and/or lanolin and removed therefrom just prior to the hardeningof the wax or waxy mixture.

3. Pre-warmed as in the above, the blocks may likewise be immersed in an open bath of the waxy mixture at a temperature of 212 F. for a. period of at least 18 to 24 hours and, omitting the application of pressure, be treated as already described.

4. Altemativeiy, the blocks may be soaked first in Just a lanolin bath and cooled then in the molten wax for the extended period of at least 18 to 24 hours and at a temperature of 212 F.

5. A modification of theimpregnating process set forth in Example 1, and using the pressure tank, is to preheat the blocks throughout and then, immersing them in the molten waxy mixture at 212 F., exhaust the pressure from the tank and allow the pressure and temperature to return slowly to normal while the blocks take inthe wax and lanolin. Like the three immediately preceeding examples, this process really takes too long but all can be used with reasonable measure of success, due in part to the fact that the blocks being treated are of short length. mostly about 2 and 2 /2 inches. Above 3 inches in length, even under the best practice, it would be extremely diflicult to secure the complete impregnation that is necessary.

6. The preferred process foncomplete saturation is that set forth in my copending application #357,663, Process for treating wood blocks for suction box covers and the like, issuedas Patent #2,3l2,978, March 2, 1943, of which the present application is a contnuation-in-part. Here the preheated blocks, evenly warmed throughout, are stacked in the tank and at a constant temperature of 212 F. are subjected to a substantial vacuum for approximately 30 minutes then under pressure of 50 pounds for from 20 to 30 minutes and removed while still hot.

From the foregoing description taken in connection with the accompanying drawing, it will be manifest that an improved end-'of-grain, thoroughly wax-impregnated wood block for a suction box top for paper making machines is provided that will fulfil all the necesary require-* ments of such a device, but-as many changes could be made in the above description and many apparently widely different embodiments of the invention may be constructed within the scope of the appended claims, without departing from the spirit or scope thereof, it is intended that all matters contained in the said accompanying specification and drawing shall be interpreted as illustrative and not in a limitative or restrictive sense.

What is claimed is:

1. For a suction box cover for a paper making machine, an end-of-grain wood block having the fibres and pores thoroughly impregnated with a mixture of wax and lanolin, the lanoline being in the proportion of about A -10%.

2. For a suction box cover for a paper making machine, an end-of-grain wood block having the fibres saturated with lanolin and the cells and pores fully loaded with a very hard paraflln wax.

3. A wood block, as set forthin claim 1, having tapered, non-clogging suction holes.

JEAN PROULX. 

